Tiled showerhead for a semiconductor chemical vapor deposition reactor

ABSTRACT

A showerhead for a semiconductor processing reactor formed by an array of showerhead tiles. Each showerhead tile has a plurality of process gas apertures, which may be in a central area of the tile or may extend over the entire tile. Each showerhead tile can be dimensioned for processing a respective substrate or a plurality of substrates or the array can be dimensioned for processing a substrate. An exhaust region surrounds the process gas apertures. The exhaust region has at least one exhaust aperture, and may include an exhaust slot, a plurality of connected exhaust slots or a plurality of exhaust apertures. The exhaust region surrounds the array of showerhead tiles, or a respective portion of the exhaust region surrounds the plurality of process gas apertures in each showerhead tile or group of showerhead tiles. A gas curtain aperture may be between the exhaust region and the process gas apertures of one of the showerhead tiles or adjacent to the central area of the tile.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 13/222,890 filed on Aug. 31, 2011 and a continuation-in-part ofU.S. patent application Ser. No. 13/222,840 filed on Aug. 31, 2011 fromboth of which the benefit of priority is claimed and which are bothhereby incorporated by reference.

TECHNICAL FIELD

The field of the present disclosure relates to semiconductor processingand showerhead reactors, particularly to showerheads for chemical vapordeposition reactors.

BACKGROUND

Various deposition and etching processes and tools are used insemiconductor wafer processing such as for integrated circuits, solarphotovoltaic cells and micro-machining. Two predominant types ofreactors used in semiconductor processing are the tube-type reactor andthe showerhead-type reactor, which are discussed in “Principles ofChemical Vapor Deposition” by Daniel M. Dobkin and Michael K. Zuraw,2003, Kluwer Academic Publishers.

Typically, a chemical vapor deposition (CVD) showerhead reactor operateson a single wafer per chamber and thus has much lower wafer throughputthan a CVD tube reactor, which handles many wafers in parallel in asingle load. In a showerhead reactor, gases are distributed to a waferfrom a showerhead (alternately, shower head). In a tube reactor, gasesare distributed to a parallel-spaced set of wafers in a boat, with thegases traveling from an inlet at one end of the tube to an exhaust atthe other end of the tube. Showerhead reactors are often run at a higherdeposition rate in order to improve throughput for commercial viability.

Tube reactors and showerhead reactors are often known as hot-wall andcold-wall reactor designs respectively, with the tube reactor normallyoperated as nearly isothermal and the showerhead reactor having largetemperature gradients from one part of the reactor to another.Generally, for plasma generation, showerhead reactors are preferred ascompared to tube reactors, as tube-type plasma reactors havedifficulties in mechanical design, particle control, electrical designand wafer handling. Tube reactors are suitable for processes requiringgood temperature uniformity and high temperatures, such as polysilicondeposition. Showerhead reactors are suitable for lower temperatureplasma-based processes including deposition of various materials andetching.

Plasma reactors often use a metallic showerhead as one plasma electrode,and a wafer in electrical connection with a chuck as the other plasmaelectrode. Walls of the chamber in which the showerhead and the waferare mounted are generally held at ground potential for safety reasons.Electrons in the plasma lose energy to the chamber walls upon collisionwith the walls. Plasma enhanced chemical vapor deposition (PECVD) isoften preferred in semiconductor processing as compared to physicalvapor deposition (PVD), as films deposited by PECVD conformally coverprocessed wafer topographies, filling trenches or holes, and havesuperior electrical properties and lower defect densities.

Plenum dimensions and diameter, angle, and placement of holes in theshowerhead affect flow of process gases. Generally, the showerhead has adiameter that is approximately the same as or is slightly larger thanthe silicon wafer or substrate being processed, as does the chucksupporting the wafer or substrate. Multiple gas plenums may be arrangedin circumferential rings in or above the showerhead, for dispensingmultiple gases without mixing in the plenum.

US Patent Application Publication No. 2010/0233879 A1 discloses asingle-wafer, multiple-showerhead, multiple-chuck reactor. A wafer ismoved to four or five different chucks for deposition of a portion of afilm at each chuck. Each showerhead introduces its own randomnonuniformities. Using several chucks averages out the randomnonuniformities.

Improvements in showerhead reactors are sought. It is a goal of thepresent invention to improve processing throughput in showerheadreactors.

SUMMARY

A goal of improving processing throughput in showerhead reactors is metwith a tiled showerhead for a semiconductor-processing showerheadreactor. A showerhead “tile” is a showerhead with an array of gasoutflow apertures. A showerhead tile can be about the same size as, orlarger than or smaller than a standard showerhead. A tiled showerheadcan be built up to a size that is larger than a standard showerhead.Some tiles can include exhaust ports and/or fluid temperature control,while other tiles rely on surrounding infrastructure for exhaust and/orfluid temperature control. Showerhead tiles enable a tiled showerhead tobe scaled upwards or downwards by adding or subtracting repeated copiesof a showerhead tile in a modular manner.

A tiled showerhead has an array of showerhead tiles that fit together ina defined area. Each of the showerhead tiles has a plurality of processgas apertures. Each tile can be dimensioned for processing a respectivesubstrate or a plurality of substrates or the entire array can bedimensioned for processing an areawise substrate. The tiled showerheadcan be used for simultaneous processing of semiconductor wafers orsimilar substrates.

In one embodiment, each showerhead tile has fluid passageways adjacentto the central area of the tile. The fluid passageways may includecooling plenums, or exhaust gas passageways connected to gas curtainapertures. Sometimes an exhaust region, with an exhaust aperture,surrounds the central area of the showerhead tile.

In a further embodiment, each showerhead tile has at least one fluidpassageway adjacent to the central area of the tile. The fluidpassageway may include cooling plenums, or gas passageways connected togas curtain apertures for reactive gas deposition on a substrate ofcorresponding size.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of an exemplary showerhead tile in accordancewith the present invention.

FIG. 2 is a top plan view of a tiled showerhead formed by an array ofthe showerhead tiles of FIG. 1.

FIG. 3 is a top plan view of a showerhead tile that is an alternateembodiment of the showerhead tile of FIG. 1.

FIG. 4 is a top plan view of a tiled showerhead that is an alternateembodiment of the tiled showerhead of FIG. 2, formed by an array of theshowerhead tile of FIG. 3.

FIG. 5 is a top plan view of a showerhead tile that is an alternateembodiment of the showerhead tiles of FIGS. 1 and 3.

FIG. 6 is a top plan view of an array of showerhead tiles formed by theshowerhead tiles of FIG. 5.

FIG. 7A is a top plan view of a tiled showerhead that is an alternateembodiment of the tiled showerheads of FIGS. 2 and 4, using arrays shownin FIG. 6.

FIG. 7B is a top plan view of another tiled showerhead that is analternate embodiment of the tiled showerhead of FIG. 2.

FIG. 8A is a top plan view of a tiled showerhead that is an alternateembodiment of the tiled showerheads of FIGS. 2, 4, and 7A, using thearrays shown in FIG. 6.

FIG. 8B is a top plan view of another tiled showerhead that is analternate embodiment of the tiled showerhead of FIG. 4.

FIG. 9 is a perspective view of a showerhead fixture, including ashowerhead assembly and a gas distribution conduit, suitable for usingthe tiled showerheads of FIG. 2, 4, 7, or 8.

FIG. 10 is a perspective view of an entry or exit port of a showerheadreactor, suitable for using the showerhead fixture of FIG. 9.

FIG. 11A is a perspective view of an entry and exit ports of twoadjoining modular showerhead reactors.

FIG. 11B is a perspective view of an entry and exit ports of the twoadjoining modular showerhead reactors of FIG. 11A with a plurality ofsubstrates.

FIG. 12 is a top plan view of semiconductor substrates being processedin series in a modular showerhead reactor.

FIG. 13 is a top plan view of semiconductor substrates being processedin parallel in a showerhead reactor of the kind shown in FIG. 10.

FIG. 14A is a top plan view of groups of semiconductor substrates beingprocessed in parallel in a showerhead reactor of the kind shown in FIG.10.

FIG. 14B is another top plan view of groups of semiconductor substratesbeing processed in parallel in a showerhead reactor of the kind shown inFIG. 10.

FIG. 14C is an additional top plan view of groups of semiconductorsubstrates being processed in parallel in a showerhead reactor of thekind shown in FIG. 10.

FIGS. 15A-15G are examples of arrays of showerhead tiles of the kindshown in FIGS. 1, 3, 5, and 6.

DETAILED DESCRIPTION

With reference to FIGS. 1-9, showerhead tiles, tiled showerheads and ashowerhead fixture in accordance with the present invention are shown.The tiled showerhead has an array of showerhead tiles in a modularareawise arrangement. A tiled showerhead is suitable for use insimultaneously processing multiple semiconductor wafers in theshowerhead reactors of FIGS. 10 and 11, thereby improving waferprocessing throughput as compared to a single-wafer showerhead reactor.Examples of semiconductor wafers or other substrates being processed ina showerhead reactor are shown in FIGS. 12-14. Examples of furtherarrays of the tiled showerheads are shown in FIGS. 15A-15G.

A tiled showerhead can process multiple substrates in a variety ofshowerhead reactors. A single fixture having a tiled showerhead can beused in a single-chamber showerhead reactor, to process multiplesubstrates in one or a series of processing actions in the chamber.Multiple tiled showerheads can be used in a long, linear showerheadreactor having multiple reaction chambers, each chamber having arespective tiled showerhead, to process multiple substrates in parallelin each chamber and in series in successive chambers. A modularshowerhead reactor, using modular reactors each having one or morechambers with respective tiled showerheads, can be assembled to processmultiple substrates in parallel in each chamber and in series insuccessive chambers. Respective chambers have physical walls, gasisolation walls and/or exhaust zones in various combinations surroundingthe chamber and/or separating the chamber from an adjacent chamber.

The showerhead tiles 100, 300 and 500 shown in FIGS. 1, 3 and 5respectively are square and have a square central area with a pluralityof process gas apertures. Such square showerhead tiles are suitable forprocessing square semiconductor wafers, such as used in certain types ofphotovoltaic solar cells, and suitable for processing roundsemiconductor wafers of a diameter less than or approximately equal tothe length of a side of the square central area with the process gasapertures. Other shapes of showerhead tiles and various regions on thetile, such as hexagonal, rectangular, polygonal or round, may be devisedby a person skilled in the art. Tiles are connected by welding and so aslight amount of tile border area is provided for a weld bead.Alternative connections can be used, such as bolting. In this regard,each tile can be surrounded by flanges for connection or for cooling orfor exhaust.

With reference to FIG. 1, the showerhead tile 100 has a square centralarea 2, with a plurality of process gas apertures 4, surrounded by asquare ring region 6. The square ring region 6 includes two fluidpassageways 8 and 10, which are adjacent to the central area 2 of theshowerhead tile 100. The square ring region 6 is surrounded by anexhaust region 12, which has a plurality of exhaust apertures 14 and isin the shape of a further square ring. The exhaust region 12 includes acontiguous exhaust slot, a plurality of connected exhaust slots or aplurality of holes of various shapes or sizes as may readily be devised.A flange 16 in the shape of a still further square ring surrounds theexhaust region 12. From the central area 2 outward, the showerhead tile100 thus has concentric regions for process gas apertures 4, fluidpassage, exhaust apertures 14 and a flange 16.

The fluid passageways 8 and 10 are used for two differing purposes inembodiments of the showerhead tile 100, namely cooling in first andthird embodiments and provision of a gas curtain in second and thirdembodiments. In a first embodiment, the two fluid passageways 8 and 10are connectable to circulate a cooling fluid, which cools the showerheadtile 100.

In a second embodiment, the two fluid passageways 8 and 10 areconnectable to a gas supply and provide an isolation gas curtain throughgas curtain apertures 20 of the showerhead tile 100. The gas curtainapertures 20 are fluidly connected to the two fluid passageways 8 and10. Hydrogen is suitable as a gas for the gas curtain. In a furtherexample, nitrogen is suitable as a gas for the gas curtain. Furthergases suitable for the gas curtain can be devised.

In a third embodiment, each of the two fluid passageways 8 and 10 actsas a cooling plenum and is open on the surface of the showerhead tile100 facing a wafer being processed. Hydrogen or other gas passingthrough the fluid passageways 8 and 10 cools the showerhead tile 100through heat transfer from the showerhead tile 100 to the gas in thecooling plenum. The hydrogen or other gas proceeds outward from thecooling plenum to form a gas curtain. Each of the two fluid passageways8 and 10 thus provides a gas curtain and a cooling to the showerheadtile 100.

With reference to FIG. 2, a tiled showerhead 200 has a three by threearray 28 of the showerhead tile 100 of FIG. 1. A flange 30 in the shapeof a square ring surrounds the array 28 of showerhead tiles 100. Thetiled showerhead 200 can be used to process a number of semiconductorwafers. In one example, the number of semiconductor wafers processed, isequal to the number of showerhead tiles in the array of showerheadtiles. In this example, there are nine showerhead tiles 100. Thus, inone example, the tiled showerhead 200 can process nine semiconductorwafers simultaneously e.g. in a three by three array of wafers, in asuitable showerhead reactor. In another example, each tile 100 of thetiled showerhead 200 can process a plurality of semiconductor wafers orsubstrates. For example, one tile of an array can process 4, 6 or 9wafers or substrates or any other desired number of wafers orsubstrates. In the example where each tile 100 of the showerhead 200processes 4 substrates, 36 substrates are processed by the tiledshowerhead 200. Where each tile 100 of the showerhead 200 processes 6substrates, 54 substrates are processed by the tiled showerhead 200 andwhere each tile 100 of the showerhead 200 processes 9 substrates, 81substrates are processed by the tiled showerhead 200.

With reference to FIGS. 3 and 4, a more compact tiled showerhead 400 canbe devised by moving the exhaust apertures from the showerhead tiles tothe tiled showerhead 400. In FIG. 3, the showerhead tile 300 has asquare central area 32 with a plurality of process gas apertures 34. Thesquare central area 32 is surrounded by a square ring region 36 thatincludes two fluid passageways 38 and 40 adjacent to the central area 32of the showerhead tile 300. The showerhead tile 300 lacks the exhaustregion of the showerhead tile 100 and is thus more compact than theshowerhead tile 100. In first, second and third variations of theshowerhead tile 300, the fluid passageways 38 and 40 perform similarfunctions and are configured similarly to the fluid passageways 8 and 10of the showerhead tile 100.

In FIG. 4, the tiled showerhead 400 has a three by three array 48 of theshowerhead tile 300 of FIG. 3. A gas curtain region 42, in the shape ofa square ring, surrounds the array 48 of showerhead tiles 300 and has aplurality of gas curtain apertures 50. An exhaust region 52, in theshape of a further square ring and with a plurality of exhaust apertures54, surrounds the gas curtain region 42 and the array 48 of showerheadtiles 300. In variations, the exhaust region 52 includes a contiguousexhaust slot, a plurality of connected exhaust slots or a plurality ofholes of various shapes or sizes as may readily be devised. A flange 56,in the shape of a still further square ring, surrounds the exhaustregion 52. As a result of using the more compact showerhead tile 300 ascompared with the showerhead tile 100, the tiled showerhead 400 is morecompact than the tiled showerhead 200.

A three by three array of wafers being processed using the tiledshowerhead 400 can be more compact than a three by three array of wafersbeing processed using the tiled showerhead 200. A showerhead reactorusing the tiled showerhead 400 can be more compact than a showerheadreactor using the tiled showerhead 200.

With reference to FIGS. 5-8, further variations of tiled shower headssuch as the tiled showerhead 700 and the tiled showerhead 800 can bedevised by grouping showerhead tiles. In FIG. 5, the showerhead tile 500has a plurality of process gas apertures 62. As depicted, the showerheadtile 500 lacks gas curtain apertures or exhaust apertures and is thusmore compact than showerhead tiles having gas curtain apertures and/orexhaust apertures. Further variations of tiled shower heads havinggrouped showerhead tiles can be devised using showerhead tiles havinggas curtain apertures, exhaust apertures or both.

In FIG. 6, a two by two array 600 of showerhead tiles 500 is formed as agrouping of showerhead tiles. In the tiled showerheads 700 and 800 inFIGS. 7A and 8B, the array 600 of showerhead tiles 500 is repeated in atwo by two array of arrays 600 of showerhead tiles 500. Various furtherarrays of arrays, arrays of groupings, groupings of arrays, groupings ofgroupings and so on can be devised by a person skilled in the art. Anarray 600 of showerhead tiles 500 can be surrounded by a combination ofperimeter exhaust regions 72 and inter-array exhaust regions 74 as shownin FIG. 7A, or all of the arrays 600 of showerhead tiles 500 can besurrounded by a perimeter exhaust region 82 as shown in FIG. 8A. Invarious examples, exhaust regions employ a plurality of exhaustapertures, a single opening or slot, multiple interconnected openings orslots or other combinations for exhausting as may be devised by a personskilled in the art. In variations, gas isolation regions can be addedsurrounding the arrays 600. Gas isolation regions can be between aportion of an exhaust region and at least one of the gas curtainapertures, such as between the exhaust region and one of the showerheadtiles, between groups of showerhead tiles, between a group of showerheadtiles and a portion of an exhaust region and so on. A flange 76, 84, 77or 85 or other region can surround the exhaust region in variousexamples.

As shown in FIG. 7B, showerhead 701 comprises fewer individualshowerhead tiles 100 than seen in showerhead 200 of Fig, 2. For example,an array of four tiles 501 can be used in the showerhead. A centralsquare ring region of each tile 100 may be surrounded by an exhaustregion 12 and the tile may have fluid passageways 8, 10 as representedby dashed lines and as discussed previously with regard to tile 100.

As shown in FIG. 8B, showerhead 801 comprises fewer individualshowerhead tiles 300 than seen in showerhead 400 of FIG. 3. For example,an array of four tiles 503 can be used in the showerhead. The array oftiles 300 may be surrounded by and exhaust region 52 and a gas curtainregion 42 and include two fluid passageways 38 and 40 represented bydashed lines as discussed previously with regard to tile 300.

With reference to FIG. 9, a gas conduit 904 with multiple branches 906provides gas flow to a showerhead assembly 902 in a showerhead fixture900. The showerhead assembly 902 includes one or more plenums 908 and910, and one or more diffuser plates 912, as well as a showerhead plate914. The showerhead assembly 902 can use a conventional showerhead orcan use one of the tiled showerheads of FIG. 2, 4, 7 or 8. Each branch906 of the gas conduit 904 provides a gas flow to a respectiveshowerhead tile or group of showerhead tiles. Conduits for a gasisolation curtain and/or an exhaust are readily devised in accordancewith the disclosure. In variations, each showerhead tile or each groupof showerhead tiles has a respective gas distribution line or multiplegas distribution lines.

Variations of the showerhead assembly 902 are dimensioned and equippedaccording to the number and arrangement of showerhead tiles in the arrayof tiles. The plenum or plenums should be large enough for an evendistribution of gases. A larger showerhead for a larger array ofshowerhead tiles should have a taller plenum, more plenums and/or morediffuser plates. Conversely, a smaller showerhead for a lesser number ofshowerhead tiles in a smaller array of showerhead tiles may have ashorter plenum, fewer plenums and/or fewer diffuser plates.

With reference to FIG. 10, a showerhead reactor 1000 can be used forsimultaneously processing multiple semiconductor wafers or othersubstrates, by employing one or more of the tiled showerhead 200, 400,700, 800 or variation thereof in each of one or more reaction chambers.One or more reaction or processing chambers, isolation zones, transitzones and/or other regions or zones are enclosed by the reactor walls1002, reactor floor 1014 and reactor lid 1004. A roller assembly 1008 orother transport mechanism moves wafers or other substrates, which may beon a wafer or substrate carrier, through the showerhead reactor 1000.Heating units 1006, such as infrared lamps, electrical resistiveheaters, inductive heating units or other heat sources as may bedevised, can heat the wafers or other substrates.

Each of the showerhead tiles 100, 300 or 500 in a tiled showerhead 200,400, 700, 701, 800 or 800 or variation thereof distributes process gasto a respective wafer or plurality of wafers or substrates in theshowerhead reactor 1000. In variations, a gas curtain is provided by thesecond or the third variation of the showerhead tile 100 as in the tiledshowerhead 200, or by the tiled showerhead 400 or examples of the tiledshowerhead 700. 701, 800 or 801. Exhaust is provided by each of theshowerhead tiles 100 in the tiled showerhead 200 or by the tiledshowerhead 400, 700, 701, 800 or 801.

With reference to FIG. 11A, a semiconductor wafer 1106 or othersubstrate or, with reference to FIG. 11B, a plurality of wafers orsubstrates 106 in can be processed in a first showerhead reactor 1102and subsequently processed in a second showerhead reactor 1104. Thewafer 1106 or plurality of wafers 1107 can be moved in a forwarddirection 1108 and transferred out of an exit 1118 of the firstshowerhead reactor 1102, then transferred into an entrance 1120 of asecond showerhead reactor 1104.

In a modular showerhead reactor, the first showerhead reactor 1102 is ashowerhead reactor module and the second showerhead reactor 1104 is afurther showerhead reactor module, which can be the of the same or ofdiffering construction and characteristics. In one embodiment of amodular showerhead reactor, the first and second showerhead reactors1102, 1104 are modules and are moved in directions 1110, 1112 towardeach other. The exit face 1114 of the first showerhead reactor 1102 isfastened to the entrance face 1116 of the second showerhead reactor 1104with appropriate hardware and sealing. A substrate or substrates canpass directly from the first showerhead reactor 1102 to the secondshowerhead reactor 1104.

With reference to FIGS. 12-14, various parallel and series processingarrangements are shown for processing one or more semiconductor wafersor other substrates in a showerhead reactor. In FIG. 12, wafers 1202,1204 and 1206 or other substrates are processed in series in theshowerhead reactor 1000 or variation thereof. Each processing region1210, 1212, 1214 is surrounded by a protection zone as provided by aperimeter protection zone 1216 and an inter-substrate protection zone1218 or an individual perimeter protection zone 1220, with eachprotection zone providing a gas isolation curtain, an exhaust or both.Each wafer 1202 moves in a forward direction 1224 from one processingregion 1210 to another processing region 1212 along a path 1222 from anentrance of the reactor to an exit of the reactor.

In FIG. 13, two wafers 1302 and 1304 or other substrates are processedand move in a forward direction 1308, 1310 in parallel along a path 1306through the showerhead reactor 1000 or variation thereof. Dimensions ofthe reactor and dimensions or arrangements of showerheads are formedaccordingly.

In FIG. 14A, a plurality of wafers 1402 or other substrates areprocessed and move in a forward direction 1408 in parallel along a path1410 through the showerhead reactor 1000 or variation thereof,dimensioned accordingly. The plurality of wafers 1402 is shown as anarray of tiles, grouped such that the array of tiles is an array ofgroups of tiles. A group 1406 of wafers is an array of four groups 1404of wafers. Each group 1404 has four wafers 1402. In one example, each ofthe sixteen wafers 1402 in the group 1406 is associated with arespective one of the showerhead tiles 500 in a tiled showerhead 700 or800, for processing when the wafers are positioned under the tiledshowerhead 700 or 800 inside of a showerhead reactor 1000. In anotherexample, each group of wafers 1404 of the larger group 1406 isassociated with a respective one of the showerhead tiles 100 or 300 in atiled showerhead 701 or 801, for processing when the wafers arepositioned under the tiled showerhead 701 or 801 inside of a showerheadreactor 1000. The sizes and shapes of the showerhead tiles varydepending on the sizes, shapes and/or number of wafers to process. Thusonly four of the showerhead tiles 100 or 300 are required to process 16substrates 1402. As an example, after the sixteen wafers 1402 in thegroup 1406 are processed in a reaction or processing zone under a tiledshowerhead 700, 701, 800 or 801, the wafers are moved to a subsequentreaction or processing zone and further processed under another tiledshowerhead applying similar or different gases and conditions.

In FIG. 14 b, a plurality of wafers 1403 or other substrates areprocessed and move in a forward direction 1408 in parallel along a path1410 through the showerhead reactor 1000 or variation thereof,dimensioned accordingly. The plurality of wafers 1403 is shown as anarray of tiles, grouped such that the array of tiles is an array ofgroups of tiles. A group 1409 of wafers is an array of four groups 1407of wafers. Each group 1407 has six wafers 1403. In one example, each ofthe twenty four wafers 1403 in the group 1407 is associated with arespective one of the showerhead tiles 500 in a tiled showerhead (notshown), for processing when the wafers are positioned under the tiledshowerhead inside of a showerhead reactor 1000. In another example, eachgroup of wafers 1407 of the larger group 1409 is associated with arespective one of the showerhead tiles 100 or 300 in a tiled showerhead701 or 801, for processing when the wafers are positioned under thetiled showerhead 701 or 801 inside of a showerhead reactor 1000. Thesizes and shapes of the showerhead tiles vary depending on the sizes,shapes and/or number of wafers to process. As an example, after thetwenty four wafers 1403 in the group 1409 are processed in a reaction orprocessing zone under a tiled showerhead 701 or 801, the wafers aremoved to a subsequent reaction or processing zone and further processedunder another tiled showerhead applying similar or differing gases andconditions.

In FIG. 14 c, a plurality of wafers 1411 or other substrates areprocessed and move in a forward direction 1408 in parallel along a path1410 through the showerhead reactor 1000 or variation thereof,dimensioned accordingly. The plurality, of wafers 1411 is shown as anarray of tiles, grouped such that the array of tiles is an array ofgroups of tiles. A group 1415 of wafers is an array of four groups 1413of wafers. Each group 1413 has nine wafers 1403. In one example, each ofthe thirty six wafers 1411 in the group 1415 is associated with arespective one of the showerhead tiles in a tiled showerhead (not shown)for processing when the wafers are positioned under the tiled showerheadinside of a showerhead reactor 1000. In another example, each group ofwafers 1413 of the larger group 1415 is associated with a respective oneof the showerhead tiles 500 in a tiled showerhead 701 or 801, forprocessing when the wafers are positioned under the tiled showerhead 701or 801 inside of a showerhead reactor 1000. The sizes and shapes of theshowerhead tiles vary in size depending on the sizes, shapes and/ornumber of wafers to process. As an example, after the thirty six wafers1411 in the group 1415 are processed in a reaction or processing zoneunder a tiled showerhead 701 or 801, the wafers are moved to asubsequent reaction or processing zone and further processed underanother tiled showerhead applying similar or differing gases andconditions.

With reference to FIGS. 15A-15G, further embodiments of the tiledshowerhead 200, 400, 700, 701, 800, or 801 use various arrays of variousshapes of showerhead tiles. FIG. 15A shows a two by two square array 160of square shapes 162. FIG. 15B shows a four by four square array 164 ofsquare shapes 166. FIG. 15C shows a one by four or a four by onerectangular array 168 of square shapes 170. A rectangular array of widthequal to one is also known as a linear array. FIG. 15D shows a two byfour or a four by two rectangular array 172 of square shapes 174. FIG.15E shows a triangular array 176 of circular shapes 178, which has onehundred and twenty degree rotational symmetry. FIG. 15F shows ahexagonal or honeycomb array 180 of circular shapes 182, which has sixtydegree, one hundred and twenty degree and one hundred and eighty degreerotational symmetry. FIG. 15G shows a hexagonal or honeycomb array 184of hexagonal shapes 186, which has one hundred and twenty degreerotational symmetry. Square arrays have ninety degree and one hundredand eighty degree rotational symmetry. Further arrays are readilydevised. Showerhead tiles may be arrayed with or without spaces betweenthe tiles or groups of tiles and with or without flanges.

Referring again to FIGS. 1-9 depicting showerhead tiles, tiledshowerheads and a tiled showerhead fixture, FIGS. 10-11 depictingshowerhead reactors, FIGS. 12-14 depicting substrates being processed inparallel and/or series and FIGS. 15A-15G depicting arrays for tilingshowerhead tiles, a full range of variations and combinations of tiledshowerheads and single-chamber, multiple-chamber, linear and modularshowerhead reactors can be appreciated. A tiled showerhead processeswafers or other substrates side-by-side in parallel. Successiveprocessing can be applied under the same showerhead in the same chamberand/or under a further showerhead in a further chamber.

In a long, linear reactor, whether designed as a single reactor or amodular reactor having multiple modules, a series of showerheads isplaced along the length of the reactor in one or more chambers. Eachchamber is widened to process wafers side-by-side, as is any passagewayfrom one chamber to another. Each tiled showerhead directs processinggas to the respective substrates. Exhaust channels or ports directexhaust gas flows from substrates. Gas isolation curtains can beprovided by gas flows emanating from tiled showerheads so equipped withgas isolation apertures. A lid of the reactor can be integrated with gasconduits, can be integrated with showerhead fixtures, or can be separatefrom such.

A standard, single-wafer showerhead reactor is usually of a cold-wall orhot-wall type. A cold-wall reactor has walls that are not expresslyheated, and can experience a condensation of particles on the cold wallsfrom reactions of the various process gases. A hot-wall reactor haswalls that are expressly heated, and can experience reactions on theheated walls.

In contrast, a “zero” or no wall reactor has a chamber with no physicalwalls, and has instead walls that are created by gas flows such as gasisolation curtains. The “zero” wall reactor has many or all of thebenefits of cold-wall and hot-wall reactors with fewer or none of thedrawbacks of either. Physical walls outside of the isolation zonesprevent contamination from the atmosphere, i.e. gases arriving fromoutside of a deposition zone, and allow overall pressure control. Thus,the “zero” wall reactor does have physical walls, but the reaction ordeposition chamber within the reactor is defined by isolation zoneshaving gas isolation curtains or other gas flows. Exhaust zones pullgases away from substrates, so that contaminants such as arsenic orother processing leftovers or byproducts are not passed along to otherwafers outside of a processing zone. Pressure balancing is applied amongprocess gas flows, exhaust gas flows and gas isolation curtain flows.Examples of tiled showerheads having provision for an exhaust gas flowand/or a gas isolation curtain flow can be used in a “zero” wallshowerhead reactor.

Isolation zones with gas curtain “walls” allow a mechanically simplerapparatus that does not have mechanical doors opening and closing when asubstrate is moved from one processing zone to another processing zone,although mechanical doors or the like could be used. As an example, adeposition e.g. an epitaxial deposition can be applied in a first zone,with a further deposition applied in a second zone, followed by cleaningin the second or in a third zone, and further followed by etching in afourth or subsequent zone, with processing zones separated by isolationzones. A “train” of substrate carriers can proceed one after the other,with substrates being processed in parallel in each processing zone, andsubstrates being processed in series in subsequent processing zones andsubsequent modules.

By combining parallel processing of a group or an array of substratesunder a tiled showerhead and serial processing through subsequentprocessing zones or modules having one or more further tiledshowerheads, throughput of substrates is greatly increased as comparedto a single-substrate showerhead reactor or as compared to a seriesprocessing single-substrate-wide showerhead reactor. Multiple examplesof a long, linear showerhead reactor or of a modular showerhead reactorincluding multiple modules, each of which uses one or more tiledshowerheads, can be arrayed horizontally or vertically or both forfurther improvements in substrate processing throughput.

One of the advantages of a modular showerhead is that very largesubstrates may be processed at a single time. For example, large areaP-N junctions can be formed, then diced into smaller pieces, or used asa large panel. A modular showerhead formed by groups of array of tileswould be appropriate to processing large substrates. Another advantageis that each showerhead tile may process a plurality of substrates.

What is claimed is:
 1. A showerhead for a semiconductor-processingreactor, comprising: an array of showerhead tiles, with each showerheadtile having a plurality of process gas apertures in a central area ofthe showerhead tile and a border, the border of each tile in contactwith and connected to a border of at least one other tile, eachshowerhead tile of the array being dimensioned for processing aplurality of substrates; and an exhaust region surrounding the processgas apertures and including a surface extending from one or more centralareas of one or more of the showerhead tiles, the exhaust region havingat least one exhaust aperture in the surface.
 2. The showerhead of claim1 wherein each showerhead tile of the array of showerhead tiles isdimensioned for processing 4, 6 or 9 substrates.
 3. The showerhead ofclaim 1 wherein the exhaust region surrounds the array of showerheadtiles.
 4. The showerhead of claim 1 wherein the exhaust region is a partof each showerhead tile and surrounds the process gas apertures of eachshowerhead tile.
 5. The showerhead of claim 1 wherein the at least oneexhaust aperture includes a plurality of exhaust apertures.
 6. Theshowerhead of claim 1 further comprising a flange surrounding theexhaust region and having a surface extending from the exhaust regionsurface.
 7. The showerhead of claim 1 wherein each showerhead tile issquare, circular, rectangular or polygonal.
 8. The showerhead of claim 1wherein each showerhead tile has at least one gas curtain aperturebetween the exhaust region and the plurality of process gas apertures.9. The showerhead of claim 1 wherein each showerhead tile includes atleast one gas curtain aperture.
 10. The showerhead of claim 1 whereinthe array of showerhead tiles is a square array.
 11. The showerhead ofclaim 1 wherein the array of showerhead tiles is a rectangular array.12. The showerhead of claim 1 wherein the array of showerhead tiles hasa rotational symmetry.
 13. A showerhead for a semiconductor-processingreactor, comprising: an array of showerhead tiles, each showerhead tilehaving a border and a plurality of process gas apertures in a centralarea of the showerhead tile with at least one fluid passageway adjacentto the central area of the showerhead tile, the border of each tile incontact with and connected to a border of at least one other tile, eachshowerhead tile of the array being dimensioned for processing aplurality of substrates; and a plurality of exhaust regions, eachexhaust region surrounding the central area of each showerhead tile,each exhaust region including a surface extending from the central areaof each showerhead tile, and each exhaust region having at least oneexhaust aperture in the surface.
 14. The showerhead of claim 13, whereineach showerhead tile of the array of showerhead tiles is dimensioned forprocessing 4, 6 or 9 substrates.
 15. The showerhead of claim 13 wherein,on each showerhead tile, the at least one fluid passageway includes twocooling passageways.
 16. The showerhead of claim 13 wherein, on eachshowerhead tile, the at least one fluid passageway includes two gaspassageways fluidly connected to gas curtain apertures.
 17. Theshowerhead of claim 13 wherein, on each showerhead tile, the at leastone fluid passageway is between a portion of the central area and aportion of the exhaust region.
 18. A showerhead for asemiconductor-processing reactor, comprising: an array of showerheadtiles, each showerhead tile having a border, a plurality of process gasapertures in a central area of the showerhead tile and at least onefluid passageway adjacent to the central area of the showerhead tile,the border of each showerhead tile in contact with and connected to aborder of at least one other showerhead tile; and an exhaust regionsurrounding the array of showerhead tiles and including a surfaceextending from the central areas of the showerhead tiles, the exhaustregion having at least one exhaust aperture in the surface.
 19. Theshowerhead of claim 18 wherein each showerhead tile of the array ofshowerhead tiles is dimensioned for processing a plurality ofsubstrates.
 20. The showerhead of claim 18 further including a gascurtain region surrounding the array of showerhead tiles and having aplurality of gas curtain apertures, wherein the exhaust region surroundsthe gas curtain region.